WO2015075765A1

WO2015075765A1 - Multilayer-film etchant, concentrated etchant, and etching method

Info

Publication number: WO2015075765A1
Application number: PCT/JP2013/006915
Authority: WO
Inventors: 真着能; 善秀小佐野; 真一郎淵上
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2013-11-25
Filing date: 2013-11-25
Publication date: 2015-05-28
Also published as: JP6128404B2; TWI624565B; CN105765107A; CN105765107B; TW201533272A; JPWO2015075765A1

Abstract

　When an etchant that alone can etch a multilayer film comprising a copper layer and a molybdenum layer is used during mass production, it is important for the cross-sectional shape of an edge after etching to satisfy the shape requirement of having a forward taper without an undercut, and that no precipitate be formed in the etchant. A multilayer-film etchant containing a copper layer and a molybdenum layer contains hydrogen peroxide, an inorganic acid, an acidic organic acid, a neutral organic acid, an amine compound, and a hydrogen peroxide decomposition inhibitor, but not an azole compound; therefore, no reaction products are generated from a reaction with the hydrogen peroxide, and no precipitates form in the etchant. Furthermore, the cross-sectional shape of the edge after etching can be formed into a desirable forward tapering shape. Containing no phosphorus compounds or fluorine compounds, the etchant will case minimal damage to the environment when disposed.

Description

Etching solution for multilayer film, etching solution and etching method

The present invention relates to a multilayer film etching solution, an etching solution, and a method for etching a multilayer film of a copper layer and a molybdenum layer used for wiring of a flat panel display such as liquid crystal and organic EL.

Aluminum has been used as a wiring material for TFTs (Thin film transistors) of flat panel displays (FPDs) such as liquid crystal and organic EL (Electro-Luminescence). In recent years, large-screen, high-definition FPDs have become widespread, and wiring materials to be used have been required to have lower resistance than aluminum. Therefore, copper having a resistance lower than that of aluminum has recently been used as a wiring material.

When copper is used as a wiring material, two problems occur: adhesion to the substrate and diffusion to the semiconductor substrate. That is, in the case of using for gate wiring, adhesion may not be sufficient between substrates such as glass even when using a sputtering method that is considered to have a relatively high impact energy to the substrate. In addition, in the case of using in source / drain wiring, there is a problem that the adhered copper is diffused to the underlying silicon, and the electrical design value of the semiconductor is changed.

In order to solve this problem, a multilayer structure in which a molybdenum layer is first formed on a substrate or a semiconductor substrate and a copper layer is formed on the molybdenum layer is currently employed.

The wiring of FPD is formed by wet etching a multilayer film formed by sputtering. This is because a large area can be formed at once, which makes it possible to shorten the process. Here, the following points are considered important for the wet etching of the wiring.
(1) High processing accuracy and uniformity.
(2) The wiring cross section after processing is a forward taper of a predetermined angle.
(3) The etching performance is unlikely to be degraded (the bath life is long) by the copper ion being contained in the etching solution.
(4) There should be little generation of precipitates.

The first item, that the processing accuracy is high and uniform, is an item which is essential for processing not only wet etching but also a minute region. The shape of the cross section of the wiring, which is the second item, is a shape necessary to form reliable wiring when collectively forming a large area FPD wiring. This is because, if the etched edge portion of the multilayer film of the copper layer and the molybdenum layer can be formed with a forward taper of 30 to 60 degrees from the substrate, an etching failure will temporarily occur, and the etching rates of copper and molybdenum Even if the balance is different, it is possible to secure a margin by which product quality can be secured.

The third item is the problem of the life of the etching solution itself. A large amount of etchant is required to etch large area substrates. These etchants are also recycled from the viewpoint of cost. If the period (life) in which the etching performance can be maintained is as long as possible, the cost is reduced.

The fourth item relates not only to the problem of maintaining the etching apparatus but also to the problem of product quality. If a deposit is generated by the etching, it will cause a pipe clogging of the etching apparatus or clog a hole of a shower nozzle for sprinkling an etching solution. These phenomena cause the operation of the etching apparatus to stop, leading to an increase in cost. In addition, when the deposit adheres on the product through the etching solution, it causes a short circuit or a break, which directly affects the quality of the product.

With regard to an etching solution for a multilayer film of a copper layer and a molybdenum layer, there is a report on an etching solution containing hydrogen peroxide and at least one selected from neutral salts and organic acids (Patent Document 1: JP-A-2002-302780). (Patent No. 4282927)).

Further, hydrogen peroxide, an organic acid, a phosphate, a water-soluble cyclic amine compound as a first additive, and a water-soluble compound containing one of an amino group and a carboxyl group as a second additive An etching solution of a copper-molybdenum film containing a predetermined amount of each of a fluorine compound and deionized water has been reported (Patent Document 2: Japanese Patent Application Laid-Open No. 2004-193620 (Patent No. 4448322)).

In addition, there is a report of an etching solution for molybdenum / copper / molybdenum nitride multiple film wiring containing hydrogen peroxide, an organic acid, a triazole compound, a fluorine compound, and ultrapure water (Patent Document 3: Japanese Patent Application Laid-Open No. 2007- 005790 (patent 5111790)).

Furthermore, (A) hydrogen peroxide, (B) a fluorine-free inorganic acid, (C) succinic acid, glycolic acid, lactic acid, malonic acid and at least one organic acid selected from malic acid, (D) carbon And an amine compound having an amino group and a hydroxyl group so that the total number of groups is 2 or more, (E) 5-amino-1H-tetrazole, and (F) a hydrogen peroxide stabilizer. An etchant for a multilayer thin film comprising a copper layer and a molybdenum layer having a pH of 2.5 to 5 has been reported (Patent Document 4: Patent No. 5051323).

Japanese Patent Laid-Open No. 2002-302780 (Patent No. 4282927) Unexamined-Japanese-Patent No. 2004-193620 (patent 4448322) Unexamined-Japanese-Patent No. 2007-005790 (patent 5111790) Patent No. 5051323

Patent Document 1 discloses that in the case of a mixed solution of hydrogen peroxide and an organic acid, copper and molybdenum can be simultaneously etched by adjusting the ratio of hydrogen peroxide, and a specific etching solution is disclosed. No composition is disclosed at all.

In

Patent Documents

2 and 3, a fluorine compound is used in the composition. Therefore, not only there is a problem that the glass substrate and the silicon substrate are also etched, but there is also a problem that the environmental load is increased when the etching solution is discarded.

Patent Document 4 discusses in detail the etching of a multilayer film of a copper layer and a molybdenum layer. However, the composition of the etching solution of Patent Document 4 has a problem that a large amount of precipitates are generated in the etching solution.

In addition, when a phosphorus compound or a fluorine compound is used as a component of the etching solution, the performance as the etching solution can be easily obtained, but the burden on the environment becomes large at the time of disposal.

The present invention has been conceived in view of the above problems, and an etching solution composition of a multilayer film including a copper layer and a molybdenum layer satisfying the points considered to be important for the wet etching of the wiring described in [Background Art]. To provide In particular, the present invention provides an etching solution which does not generate precipitates in the etching solution and does not increase the load on the environment at the time of disposal, and a concentration solution thereof and an etching method.

More specifically, the etching solution for a multilayer film containing a copper layer and a molybdenum layer according to the present invention,
With hydrogen peroxide,
Inorganic acid,
With an acidic organic acid,
Neutral organic acid,
An amine compound,
It is characterized by including a hydrogen peroxide decomposition inhibitor.

In addition, the etching solution according to the present invention can be configured in the form of a concentrated solution so as not to be bulky during storage or transfer. More specifically, the etching solution for a multilayer film comprising a copper layer and a molybdenum layer according to the present invention,
Inorganic acid,
With an acidic organic acid,
Neutral organic acid,
An amine compound,
Hydrogen peroxide decomposition inhibitor,
It is characterized by containing water.

In addition, the etching method for a multilayer film including a copper layer and a molybdenum layer according to the present invention,
Inorganic acid,
With an acidic organic acid,
Neutral organic acid,
An amine compound,
Preparing an etching solution containing a hydrogen peroxide decomposition inhibitor and water, water, and hydrogen peroxide;
It is characterized in that it includes a step of bringing the etching solution for multilayer film into contact with the substrate to be treated.

In the etching solution according to the present invention, the cross-sectional shape of the etched wiring becomes forward tapered, and the shape is maintained even if it is over-etched. Moreover, since it is a structure which does not contain the azole compound which produces a precipitate when used with hydrogen peroxide, a precipitate does not generate | occur | produce in an etching liquid and problems, such as piping clogging and the hole clogging of a shower nozzle, generate | occur | produce. Therefore, there is no need to stop the operation of the etching apparatus due to the generation of precipitates, and stable production is possible.

Further, since the etching concentrate according to the present invention does not contain hydrogen peroxide and a predetermined amount of water from the above-mentioned etching solution, it can be stored or transported without being bulky and causing almost no change over time. Further, since the etching concentrate and the hydrogen peroxide can be handled separately, it is possible to easily adjust the concentration of the etching solution whose component concentration has been changed by use.

In the etching method according to the present invention, since the etching concentrate and the hydrogen peroxide solution are mixed to prepare the etching solution and the substrate is brought into contact with the substrate to be treated, the etching solution having a stable composition can be prepared at any time. The cross section of the formed wiring has a forward taper, and even if it is over-etched, the taper angle can be etched while maintaining a suitable range of angles.

In addition, since the etching solution according to the present invention does not contain a substance such as a phosphorus compound, a chlorine compound or a fluorine compound, there is an advantage that the load on the environment is light when discarded.

It is a conceptual diagram showing the cross section of the wiring formed by the etching.

The etching solution according to the present invention will be described below. The following description shows one embodiment of the etching solution according to the present invention, and the following embodiments and examples may be modified without departing from the spirit of the present invention. The etching solution according to the present invention is characterized in that precipitates are not generated in the etching solution. As shown in the examples described later, it was strongly suggested that the cause of the precipitate is a reaction product of an azole compound and hydrogen peroxide. Therefore, the etching solution according to the present invention does not contain an azole compound.

In addition, phosphorus compounds, fluorine compounds and chlorine compounds are also not included to reduce the environmental burden. However, it may be included if the etching performance and product quality are not affected or the environmental load at the time of disposal is below the standard defined in each country. Also, such amount may be interpreted as not including.

<Hydrogen peroxide>
In the etching of copper, copper is oxidized to form copper oxide (CuO), which is dissolved by an inorganic acid. In addition, the etching of molybdenum is oxidized to form molybdenum oxide (MoO 3), which is dissolved in water. Hydrogen peroxide is used as an oxidizing agent to oxidize copper and molybdenum. Hydrogen peroxide is preferably 3.50% by mass to 5.80% by mass of the total amount of the etching solution. Hydrogen peroxide is also referred to as "peroxide".

<Inorganic acid>
Inorganic acids are used to dissolve oxidized copper. Phosphorus compounds and fluorine compounds are not used in order not to affect the substrate materials such as glass and silicon, and to reduce the environmental burden when discarding the etching solution. Also, hydrochloric acid is not used. Nitric acid and sulfuric acid can be suitably used. The inorganic acid is contained in the range of 0.01% by mass to 0.50% by mass, preferably 0.02% by mass to 0.20% by mass, with respect to the total amount of the etching solution.

<Organic acid>
The organic acid component mainly serves to adjust the taper angle of the cross section of the etched wiring. In addition, it is considered that it also has a function of suppressing the decomposition of hydrogen peroxide to some extent. As the organic acid component, a combination of an acidic organic acid and a neutral organic acid is used. Moreover, you may combine both an acidic organic acid and a neutral organic acid.

Preferred examples of the organic acid which can be used include aliphatic carboxylic acids having 1 to 18 carbon atoms, aromatic carboxylic acids having 6 to 10 carbon atoms, and amino acids having 1 to 10 carbon atoms.

Examples of aliphatic carboxylic acids having 1 to 18 carbon atoms include formic acid, acetic acid, propionic acid, lactic acid, glycolic acid, glycolic acid, diglycolic acid, pyruvic acid, malonic acid, butyric acid, hydroxybutyric acid, tartaric acid, succinic acid, malic acid and maleic acid , Fumaric acid, valeric acid, glutaric acid, itaconic acid, adipic acid, caproic acid, adipic acid, citric acid, propanetricarboxylic acid, trans-aconitic acid, enanthate, caprylic acid, lauric acid, myristic acid, palmitic acid, stearin Preferred are acid, oleic acid, linoleic acid, linolenic acid and the like.

Preferred examples of the aromatic carboxylic acid having 6 to 10 carbon atoms include benzoic acid, salicylic acid, mandelic acid, phthalic acid, isophthalic acid and terephthalic acid.

Further, as the amino acid having 1 to 10 carbon atoms, carbamic acid, alanine, glycine, asparagine, aspartic acid, sarcosine, serine, glutamine, glutamic acid, 4-aminobutyric acid, iminodibutyric acid, arginine, leucine, isoleucine, nitrilotriacetic acid, etc. Is preferably mentioned.

Among the above organic acids, glycolic acid, aspartic acid, glutamic acid and citric acid can be suitably used as the acidic organic acid. In particular, glycolic acid, aspartic acid, and glutamic acid can obtain suitable properties by using three types simultaneously. The acidic organic acid is preferably contained in an amount of 1% by mass to 7% by mass with respect to the total amount of the etching solution.

When glycolic acid, aspartic acid and glutamic acid are simultaneously used, glycolic acid is preferably contained in an amount of 1 to 5% by mass, more preferably 1.50 to 2.50% by mass based on the total amount of the etching solution. It is good to let The content of aspartic acid is preferably 0.10% by mass to 1.00% by mass, more preferably 0.20% by mass to 0.50% by mass, based on the total amount of the etching solution. The glutamic acid is preferably 0.1% by mass to 1.0% by mass, more preferably 0.60% by mass to 0.90% by mass, based on the total amount of the etching solution.

Moreover, glycine, alanine or beta-alanine can be suitably used as a neutral organic acid. The neutral organic acid is preferably contained in an amount of 0.10% by mass to 3.00% by mass with respect to the total amount of the etching solution.

Moreover, you may combine 1 type of glycolic acid and another acidic organic acid, or 1 type of neutral organic acids other than the above. In that case, glycolic acid is preferably contained in an amount of 1% by mass to 5% by mass, more preferably 1.50% by mass to 2.30% by mass, based on the total amount of the etching solution. On the other hand, the content of the acidic organic acid or neutral organic acid is preferably 0.10% by mass to 1.00% by mass, more preferably 0.3% by mass to 0.7% by mass, based on the total amount of the etching solution. Is good.

<Amine compound>
The amine compound is mainly responsible for adjusting the pH of the etching solution. As the amine compound, one having 2 to 10 carbon atoms can be suitably used. More specifically, ethylenediamine, trimethylenediamine, tetramethylenediamine, 1,2-propanediamine, 1,3-propanediamine, N, N-dimethyl-1,3-propanediamine, N, N-diethyl-1 , 3-propanediamine, 1,3-diaminobutane, 2,3-diaminobutane, pentamethylenediamine, 2,4-diaminopentane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, N-methyl Ethylenediamine, N, N-dimethylethylenediamine, trimethylethylenediamine, N-ethylethylenediamine, N, N-diethylethylenediamine, triethylethylenediamine, 1,2,3-triaminopropane, hydrazine, tris (2-aminoethyl) amide Polyamines such as tetra (aminomethyl) methane, diethylenetriamine, triethylenetetramine, tetraethylpentamine, heptaethyleneoctamine, nonaethylene decamine, diazabicycloundecene and the like; ethanolamine, N-methylethanolamine, N-methyldiethanolamine N-ethyl ethanolamine, N-aminoethyl ethanolamine, N-propyl ethanolamine, N-butyl ethanolamine, diethanolamine, triethanolamine, 1-amino-2-propanol, N-methylisopropanolamine, N-ethylisopropanol Amine, N-propylisopropanolamine, 2-aminopropan-1-ol, N-methyl-2-amino-propan-1-ol, N-ethyl-2-amino Propan-1-ol, 1-aminopropan-3-ol, N-methyl-1-aminopropan-3-ol, N-ethyl-1-aminopropan-3-ol, 1-aminobutan-2-ol, N -Methyl-1-aminobutan-2-ol, N-ethyl-1-aminobutan-2-ol, 2-aminobutan-1-ol, N-methyl-2-aminobutan-1-ol, N-ethyl-2-aminobutane- 1-ol, 3-aminobutan-1-ol, N-methyl-3-aminobutan-1-ol, N-ethyl-3-aminobutan-1-ol, 1-aminobutan-4-ol, N-methyl 1-aminobutane -4-ol, N-ethyl-1-aminobutan-4-ol, 1-amino-2-methylpropan-2-ol, 2-amino-2-methylprop -1-ol, 1-aminopentan-4-ol, 2-amino-4-methylpentan-1-ol, 2-aminohexan-1-ol, 3-aminoheptan-4-ol, 1-aminooctane -2-ol, 5-aminooctan-4-ol, 1-aminopropane-2,3-diol, 2-aminopropane-1,3-diol, tris (oxymethyl) aminomethane, 1,2-diaminopropane- Preferred examples include alkanolamines such as 3-ol, 1,3-diaminopropan-2-ol, 2- (2-aminoethoxy) ethanol, 2- (2-aminoethylamino) ethanol, and diglycolamine. It can be used alone or in combination of two or more. Among these, 1-amino-2-propanol is particularly preferable. The amine compound is preferably contained in an amount of 0.50% by mass to 2.00% by mass, more preferably 1.00% by mass to 1.90% by mass, based on the total amount of the etching solution.

<Hydrogen peroxide decomposition inhibitor>
In the etching solution according to the present invention, hydrogen peroxide is used as the oxidizing agent. Since hydrogen peroxide is self-decomposable, a decomposition inhibitor that suppresses its decomposition is added. It is for lengthening the life of the etching solution. As a main hydrogen peroxide decomposition inhibitor, in addition to urea based hydrogen peroxide stabilizers such as phenylurea, allylurea, 1,3-dimethylurea and thiourea, phenylacetic acid amide, phenylethylene glycol, 1-propanol, Lower alcohols such as 2-propanol and the like are preferably mentioned.

In particular, phenylurea is preferred, and more preferably phenylurea and 1-propanol are used in combination. The hydrogen peroxide decomposition inhibitor is preferably contained in an amount of 0.05% by mass to 0.20% by mass, more preferably 0.07% by mass to 0.12% by mass with respect to the total amount of the etching solution if it is phenylurea. % Is good. The lower alcohol is preferably contained in an amount of 0.10% by mass to 2.00% by mass, and more preferably in an amount of 0.80% by mass to 1.20% by mass.

These substances are considered to act on hydrogen peroxide and to suppress the decomposition of hydrogen peroxide by suppressing the generation of radicals. When phenyl urea is contained in an amount of more than 0.20% by mass with respect to the total amount of the etching solution, the phenyl group reacts with hydrogen peroxide to generate precipitates different from the reaction product of the azole compound and hydrogen peroxide.

Chelating agent
The decomposition of hydrogen peroxide is promoted by the etching of Cu and Mo and dissolution in the etching solution. The chelating agent is considered to suppress the decomposition of hydrogen peroxide by coordinating to a metal ion such as Cu or Mo and preventing the metal ion from contacting hydrogen peroxide. Therefore, in the present specification, the chelating agent may be considered as a hydrogen peroxide decomposition inhibitor.

As the chelating agent, an aluminocarboxylic acid chelating agent such as ethylenediaminetetraacetic acid (EDTA), hydroxyethyl iminodiacetic acid (HIDA), ethylenediamine-N, N'-disuccinic acid (EDDS) is suitably used. The chelating agent is preferably contained in an amount of 0.50% by mass to 1.00% by mass, more preferably 0.60% by mass to 0.90% by mass, based on the total amount of the etching solution.

<Polyether>
Polyethers can be inhibitors of the etch rate of Cu. The use of polyether reduces the etching cross-sectional taper angle, so that it can be suitably used to adjust the taper angle. In particular, when there is sulfuric acid as an inorganic acid, the effect is large. Polyethylene glycol (PEG) can be suitably used as the polyether. The polyethylene glycol is preferably contained in an amount of 0.10% by mass to 0.50% by mass, more preferably 0.20% by mass to 0.40% by mass, based on the total amount of the etching solution.

<Copper ion>
In the etching solution according to the present invention, it was confirmed that when the etching progresses and Cu ions or Mo ions are contained, the etching rate changes according to the increase of the Cu ion concentration. Since the operation of the etching apparatus is controlled by adding the etching concentrate and the hydrogen peroxide solution so that the change of the etching rate falls within a certain allowable range, the condition of the new solution should be within this tolerance. Is preferred. Therefore, the etching solution may contain Cu ions in a predetermined range. Specifically, it is preferable to easily assume a change in etching rate if the Cu ion is contained in an amount of 500 ppm to 7000 mmp, preferably 2000 ppm to 4000 ppm with respect to the total amount of the etching solution.

<Others>
In addition to these components, various additives which are usually used may be added to the etching solution of the present invention as long as water and etching performance are not impaired. Since water is intended for precision processing, it is desirable that there be no foreign matter present. Pure water or ultrapure water is preferred.

<PH, temperature>
The etching solution according to the present invention is preferably used in the range of pH 2 to 5, more preferably pH 3 to 4.5. The etching solution according to the present invention can be used between 18 ° C and 40 ° C. The temperature is more preferably 18 ° C. to 35 ° C., and most preferably 20 ° C. to 32 ° C.

<Save>
Hydrogen peroxide is used in the etching solution according to the present invention. Hydrogen peroxide self decomposes. Therefore, the etching solution contains a hydrogen peroxide decomposition inhibitor. However, at the time of storage, the hydrogen peroxide solution and the other liquid may be stored separately. Alternatively, a raw material from which hydrogen peroxide and copper ions have been removed (referred to as "etching liquid raw material") and water may be mixed to prepare a solution of the etching liquid raw material. This solution may be water in a proportion smaller than the proportion of water in the etching solution shown in the examples described later.

A solution of an etching solution raw material prepared by mixing an etching solution raw material and water is called "etching concentrate". The etching concentrate has a smaller volume than the etching solution due to the absence of hydrogen peroxide, which is convenient for storage and transfer. Furthermore, in order to further reduce the volume during storage and transfer, the "etching concentrate" may be a "etching concentrate" in which water is reduced. The etching highly concentrated solution refers to one containing 20% to 70% of water. The etch concentrate contains more than 70% water. Therefore, the etching solution of the present invention may be completed by combining the etching concentrate and the hydrogen peroxide solution, or may be completed by combining the etching highly concentrated solution, the water, and the hydrogen peroxide solution.

<Etching method>
An object using the etching solution according to the present invention is a multilayer film of a copper layer / molybdenum layer in which molybdenum is a lower layer and copper is an upper layer. The thickness of the lower molybdenum layer is thinner than the thickness of the upper copper. When the thickness of the lower layer is t0 and the thickness of the upper layer is t1, the range of t0 / t1 is in the range of 0.01 to 0.2. If the range of t0 / t1 is out of this range and the Mo layer is too thick, residues of the Mo layer tend to be generated, and conversely, if it is too thin, the Cu layer does not serve as an underlayer.

There are no particular limitations on the substrate and the underlayer on which the molybdenum layer and the copper layer are formed, and glass, silicon, amorphous silicon, IGZO (Indium, Gallium, Gallium, Zinc, oxygen ( It may be a metal oxide such as an amorphous semiconductor composed of Oxide).

The etchant according to the present invention can be stored by storing the hydrogen peroxide solution, the etching high concentrate and the water (the hydrogen peroxide solution and the etching concentrate may be separated) separately during storage. Become. Therefore, in actual use, these are mixed to complete the etching solution. The method of preparation is not limited as long as the concentration of hydrogen peroxide finally reaches a predetermined concentration.

As an example, an etching concentrate prepared by mixing an etching solution raw material with a fixed amount of water is prepared. The hydrogen peroxide is usually supplied as a hydrogen peroxide solution having a concentration higher than the hydrogen peroxide concentration of the etching solution according to the present invention. Therefore, the hydrogen peroxide solution and the etching concentrate are prepared in predetermined amounts. This step may be called a step of preparing a multilayer film etching solution. Alternatively, the etching solution may be prepared by mixing an etching high concentration solution higher in concentration than the etching concentration solution, water, and a hydrogen peroxide solution.

Copper ions may be mixed at any time when preparing etching concentrate (or etching high concentrate) with etching solution raw material and water, or when preparing etching solution with etching concentrate and hydrogen peroxide solution. it can. Of course, it may be added after preparing the etching solution. In the case where the etching concentrate and the hydrogen peroxide solution are additionally added to the etching solution already used, it is not necessary to put copper ions. This is because copper ions already exist in the etching solution.

When the etching is performed, the etching solution is used at pH 2 to 5 and 18 ° C. to 40 ° C. as described above. Therefore, it is desirable that the object to be etched be preheated to this temperature. The method for bringing the substrate to be treated into contact with the etching solution is not particularly limited. As in the shower type, the etching solution may be dispersed to the substrate to be processed from above, or a method of dipping the substrate to be processed in a pool of etching solution may be used. This step may be called a step of bringing the etching solution for multilayer film into contact with the substrate to be treated.

In addition, with a to-be-processed substrate, a molybdenum layer (Mo layer) and a copper layer (Cu layer) are laminated on base materials, such as glass, and the pattern of the resist layer for pattern formation is formed in this laminated film. The substrate in the

<Description of various evaluation methods>
For the etching solution according to the present invention, the etching rate (nm / min) of copper and molybdenum, taper angle (°) of the cross section of the etched wiring, undercutting of the molybdenum layer, molybdenum layer remaining on the substrate ( The evaluation was made in terms of “Mo residue”, over etching resistance, presence or absence of precipitates, and hydrogen peroxide decomposition rate (% by mass / day).

The etching rate was measured as follows. First, a single-layer film was formed to a thickness of 300 nm for copper and 150 nm for molybdenum by sputtering on a silicon wafer on which a thermal oxide film of 100 nm was formed. The copper film and the molybdenum film were brought into contact with an etching solution at 30 ° C. (or 35 ° C. depending on a comparative example) for 20 to 60 seconds.

The resistance value of the film before and after etching was measured using a 4-terminal 4-probe method resistivity meter (Mitsubishi Chemical Analytech: MCP-T610 type) of a constant current application method. The change in film thickness was calculated from the change in resistance value to calculate the etching rate.

The taper angle was measured as follows. First, a molybdenum layer was formed to a thickness of 20 nm by a sputtering method on a glass substrate, and a copper layer was subsequently formed to a thickness of 300 nm, thereby forming a Cu / Mo multilayer film sample. A resist patterned in a wiring shape was formed on this copper layer, and used as a substrate for taper angle evaluation. That is, the taper angle evaluation substrate comprises a substrate, a molybdenum layer, a copper layer thereon, and a patterned resist layer on the copper layer. Etching was performed by immersing the base material for evaluation of taper angle in an etching solution for the time of just etching. After the sample after etching was washed and dried, the wiring portion was cut and the cut surface was observed.

The observation of the cut surface was performed using an SEM (Scanning Electron Microscope) (manufactured by Hitachi: SU 8020) under conditions of an acceleration voltage of 1 kV and 30,000 to 50,000 times. Just etching is the time from the start of etching to the passage of light through the film. The point in time when the film transmitted light was checked visually.

The cross-sectional shape is shown in FIG. As shown in FIG. 1A, an angle 5 between the substrate 1 and the etched inclined surface 6 is defined as a taper angle (°). When the taper angle was 30 to 60 °, it was judged as a circle (o). If it was out of the range of this angle, it was judged as cross (x). Note that "Mar" means success or pass, and "cross" means failure or fail. The same is true for the following evaluations. In FIG. 1A, the Mo layer is represented by 3; the Cu layer is represented by 2; and the resist layer is represented by 4.

The undercut of the molybdenum layer refers to a state (reverse taper) in which the space between the molybdenum layer 3 and the substrate 1 is etched faster than the copper layer, as indicated by reference numeral 10 in FIG. 1 (b). The evaluation can be performed simultaneously with the evaluation of the taper angle. The undercut of the molybdenum layer was judged as a circle (o) if it was not found by observation at 30,000 to 50,000 times the SEM, and it was judged as a cross when it was found.

The residue of Mo was determined to be x (x) when the residue was confirmed and x (circle) when it was not confirmed by observation with an optical microscope and SEM. The optical microscope was observed at a magnification of about 100 times by bright field observation and dark field observation. Moreover, in SEM, it observed by 30,000 to 50,000 times.

Overetching resistance (also referred to as "O.E. resistance") refers to the taper angle when etched for twice the time taken for just etching, the undercut of the molybdenum layer, and Mo residue, all If it is evaluation, it was judged as circle (○). If any one was judged "cross", it was marked as cross (x).

After preparing the etching solution, the presence or absence of the precipitate was left to stand at room temperature in the bottle for a predetermined time (several days) after the preparation of the etching solution, and it was visually judged whether the precipitate was generated in the bottle. When precipitates are generated, the etching solution is filtered through filter paper, the foreign matter remaining on the filter paper is washed with pure water, dried at room temperature, and the obtained crystals or powder are FT-IR (IR affinity manufactured by Shimadzu Corporation) ) And SEM-EDX (manufactured by Horiba, Ltd.). When the precipitate was not visually observed, it was judged as a circle (○), and when visually confirmed, it was judged as a cross (×).

It is important that the etching solution does not generate precipitates and that the cross-sectional shape of the wiring is appropriate, but in order to extend the bath life, the decomposition rate of hydrogen peroxide is also an important item. Here, the hydrogen peroxide decomposition rate was also examined as an evaluation item for reference.

Hydrogen peroxide decomposition rate, hydrogen peroxide concentration immediately after the preparation of the etching solution and after a predetermined time (about 24h), the titrant is potassium permanganate, automatic titrator (GP-200 made by Mitsubishi Chemical Analytech Co., Ltd.) It measured using. Then, the decomposition rate was calculated from the amount of change in the hydrogen peroxide concentration.

When the reduction amount of the hydrogen peroxide concentration after 24 hours (day) is less than 1.0% by mass, it is evaluated as a circle (○), and when it is 1.0% by mass or more, it is evaluated as a cross (×). In addition, even if the hydrogen peroxide decomposition rate is x, it may be said that the etching solution according to the present invention is used if the other item is a circle. In addition, although it did not satisfy the conditions of a round evaluation about all the evaluations, in the case of a value very close to the boundary value, it was evaluated as a triangle (Δ).

Example 1
0.06 mass% of sulfuric acid,
2.50 mass% of glycolic acid,
0.44% by weight of aspartic acid,
0.87% by mass of glutamic acid,
0.66% by mass of β-alanine,
1.61% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
0.88% by mass of ethylenediaminetetraacetic acid (hereinafter also referred to as "EDTA")
The etching liquid raw material which consists of these is mixed with 92.87 mass% of water, and the etching concentrate was prepared.

35% hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 5.30% by mass. Further, copper sulfate was added to prepare a copper ion concentration of 2000 ppm. The solution temperature was 30 ° C. The concentration of each component in the entire etching solution and the result of each evaluation item are shown in Table 1.

(Example 2)
0.07% by weight of sulfuric acid,
2.50 mass% of glycolic acid,
0.45% by mass of aspartic acid,
0.88% by weight of glutamic acid,
0.66% by mass of β-alanine,
1.61% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
0.88% by mass of ethylenediaminetetraacetic acid
0.33% by mass of polyethylene glycol (hereinafter also referred to as "PEG")
The etching liquid raw material which consists of these is mixed with 92.51 mass% of water, and the etching concentrate was prepared.

(Example 3)
0.19% by mass of nitric acid,
2.05% by weight of glycolic acid,
0.44% by weight of aspartic acid,
0.90% by mass of glutamic acid,
0.66% by mass of β-alanine,
1.94% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
0.87% by mass of ethylenediaminetetraacetic acid
The etching liquid raw material which consists of these is mixed with 92.84 mass% of water, and the etching concentrate was prepared.

(Example 4)
0.18% by mass of nitric acid,
2.55% by weight of glycolic acid,
0.45% by mass of aspartic acid,
0.91% by mass of glutamic acid,
0.69% by mass of β-alanine,
1.66% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
1.20 mass% of 1-propanol
The etching liquid raw material which consists of these is mix | blended with 92 * 25 mass% of water, and the etching concentrate was prepared.

(Example 5)
0.05 mass% of sulfuric acid,
2.47% by weight of glycolic acid,
0.44% by weight of aspartic acid,
0.87% by mass of glutamic acid,
1.17% by weight of glycine,
1.61% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
0.87% by mass of ethylenediaminetetraacetic acid
The etching liquid raw material which consists of these was mixed with 92.41 mass% of water, and the etching concentrate was prepared.

(Example 6)
0.07% by weight of sulfuric acid,
2.46% by weight of glycolic acid,
0.44% by weight of aspartic acid,
0.87% by mass of glutamic acid,
1.74% by mass of β-alanine,
1.58% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
The etching liquid raw material which consists of these is mixed with 92.73 mass% of water, and the etching concentrate was prepared.

(Example 7)
0.07% by weight of sulfuric acid,
2.50 mass% of glycolic acid,
0.61% by weight of citric acid,
1.58% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
The etching liquid raw material which consists of these is mixed with 95.13 mass% of water, and the etching concentrate was prepared.

(Example 8)
0.07% by weight of sulfuric acid,
2.27% by weight of glycolic acid,
0.66% by mass of β-alanine,
1.94% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
0.87% by mass of ethylenediaminetetraacetic acid
0.34 mass% of polyether
The etching liquid raw material which consists of these is mix | blended with 93.74 mass% of water, and the etching concentrate was prepared.

<Comparative example of use of azole compound>
(Comparative example 1)
5.62% by weight of glycolic acid,
5.20% by weight of glycine,
1.31% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
0.13 mass% of 5 amino 1H tetrazole
The etching liquid raw material which consists of these is mixed with 87.63 mass% of water, and the etching concentrate was prepared.

35% hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 5.30% by mass. Further, copper sulfate was added to prepare a copper ion concentration of 2000 ppm. The solution temperature was 35 ° C. The concentration of each component in the entire etching solution and the result of each evaluation item are shown in Table 2.

(Comparative example 2)
3.91 mass% of nitric acid,
4.33% by weight of glycine,
3.86% by weight of 1-amino-2-propanol,
0.11% by mass of phenylurea,
0.11 mass% of 5 amino 1H tetrazole
The etching liquid raw material which consists of these is mixed with 87.68 mass% of water, and the etching concentrate was prepared.

(Comparative example 3)
2.42% by mass of glycolic acid,
1.25% by weight of glycine,
0.67% by mass of 1-amino-2-propanol,
0.12% by mass of phenylurea,
0.09 mass% of 5 amino 1H tetrazole
The etching liquid raw material which consists of these is mix | blended with 95.45 mass% of water, and the etching concentrate was prepared.

(Comparative example 4)
2.65% by weight of glycolic acid,
1.00% by mass of glycine,
0.82% by mass of β-alanine,
0.39% by mass of 1-amino-2-propanol,
0.12% by mass of phenylurea,
0.12 mass% of 5 amino 1H tetrazole
The etching liquid raw material which consists of these is mix | blended with 94.90 mass% of water, and the etching concentrate was prepared.

(Comparative example 5)
0.12% by mass of nitric acid,
2.45% by weight of wenic acid,
2.62% by mass of 1-amino-2-propanol,
0.08% by mass of phenylurea,
0.29 mass% of 5 amino 1H tetrazole
The etching liquid raw material which consists of these is mix | blended with 94.44 mass% of water, and the etching concentrate was prepared.

(Comparative example 6)
0.08 mass% nitric acid,
2.20% by weight of glycolic acid,
3.98% by weight of malonic acid,
1.01% by mass of lactic acid,
2.64% by mass of 1-amino-2-propanol,
0.12% by mass of phenylurea,
0.14 mass% of 5 amino 1H tetrazole
The etching liquid raw material which consists of these is mix | blended with 89.83 mass% of water, and the etching concentrate was prepared.

35% hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 5.30% by mass. Further, copper sulfate was added to prepare a copper ion concentration of 2000 ppm. The solution temperature was 35 ° C. The concentration of each component in the entire etching solution and the result of each evaluation item are shown in Table 2.
<Comparative example of no azole compound>

(Comparative example 7)
2.65% by weight of glycolic acid,
1.00 mass% of lactic acid,
2.52% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
The etching liquid raw material which consists of these is mixed with 93.72 mass% of water, and the etching concentrate was prepared.

35% hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 5.30% by mass. Further, copper sulfate was added to prepare a copper ion concentration of 2000 ppm. The solution temperature was 35 ° C. The concentration of each component in the entire etching solution and the result of each evaluation item are shown in Table 3.

(Comparative example 8)
3.54% by weight of malonic acid,
1.40% by weight of glycine,
1.64% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
The etching liquid raw material which consists of this is mixed with 93.31 mass% of water, and the etching concentrate was prepared.

(Comparative example 9)
Citric acid 3.61% by mass,
1.43% by weight of glycine,
1.64% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
The etching liquid raw material which consists of these is mixed with 93.21 mass% of water, and the etching concentrate was prepared.

(Comparative example 10)
4.73% by mass of lactic acid,
1.39 mass% of glycine,
1.72% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
The etching liquid raw material which consists of these was mixed with 92.05 mass% of water, and the etching concentrate was prepared.

(Comparative example 11)
2.80% by weight of glycolic acid,
1.41% by mass of glycine,
1.25% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
The etching liquid raw material which consists of these is mix | blended with 94.43 mass% of water, and the etching concentrate was prepared.

<Result>
Examples 1 to 8 are etching solutions according to the present invention. Since it does not contain an azole compound, it does not form a reactant with hydrogen peroxide, and there is no precipitate. As acidic organic acids, glycolic acid, aspartic acid and glutamic acid were simultaneously used. Among these, in those further using EDTA or 1 propanol (Examples 1 to 5), there are no precipitates, and in addition, the taper angle, the Mo undercut, the Mo residue, the O. E. All items of resistance were also evaluated as a circle. Furthermore, the hydrogen peroxide decomposition rate was also less than 0.1% by mass / day, and the desired result could be obtained.

Further, since the over-etching resistance was good, etching could be performed while maintaining a good taper angle from the time spent for just etching to twice the time. In addition, even if the film thickness ratio (t0 / t1) of Mo and Cu is different from that in the case of the embodiment (20/300), the film thickness ratio of the etching solution of these embodiments is from 0.01 to 0.2 The taper angle of 30 ° to 60 ° could be realized.

Example 6 is different from Example 5 in that the neutral organic acid was replaced with glycine by β-alanine, and EDTA was not added. When EDTA was withdrawn, the decomposition rate of hydrogen peroxide (% by weight / day) exceeded 1.0% by weight / day. However, the cross-sectional shape of the etched wiring was good.

Examples 7 and 8 are examples in which the etching rate of Cu and Mo was adjusted using glycolic acid and citric acid or glycolic acid and β-alanine, and the taper angle could be formed in a suitable range. However, the hydrogen peroxide decomposition rate slightly exceeded 1.0% by mass / day. From these facts, the etching solution according to the present invention may at least contain glycolic acid as an organic acid, and may be said to have hydrogen peroxide, an inorganic acid, an amine compound and a hydrogen peroxide stabilizer. Also, chelating agents may be included.

Comparative Examples 1 to 6 are examples in which an azole compound is contained. As an azole compound, 5 amino 1H tetrazole was used. The effect of using the azole compound is that the etching rate of Mo can be increased while suppressing the etching rate of Cu. Therefore, the balance with the inorganic acid enables control of the taper angle.

In Comparative Examples 1 to 5, the etching rate of Mo was large and the taper angle was large. In Comparative Example 6, a mixture of glycolic acid, malonic acid and lactic acid was used in order to enhance only the etching rate of copper with a well-adjusted composition. In the comparative example 6, the taper angle obtained a suitable result. However, the etching rate of Mo was still high, and when the over-etching was performed, a slight undercut of the Mo layer occurred.

The compositions of Comparative Examples 1 to 6 were such that the taper angle could be adjusted, but the azole compound and hydrogen peroxide reacted to generate a precipitate.

Comparative Examples 7 to 11 are examples in which the azole compound is not contained. As shown in Comparative Examples 1 to 6, the etching rate of Cu and Mo could be adjusted by the combination of the inorganic acid and the azole compound. In Comparative Examples 7 to 11, in the case where the azole compound is not used, the etching rates of Cu and Mo are adjusted by adjusting the organic acid and the amine. The amine used 1 amino 2-propanol.

In Comparative Example 7, glycolic acid and lactic acid were used as the organic acid, but the taper angle was small. In Comparative Example 8, malonic acid and glycine were used, but the etching rate of Cu was too high and no film was left. Although the types of neutral organic acid and acidic organic acid were also changed in Comparative Examples 9 to 11, the etching rate of Cu was high, and the taper angle could not obtain a good shape. However, since no azole compound was contained, no precipitate was generated.

The examples do not use an azole compound as demonstrated in Comparative Examples 7 to 11, so no precipitates are generated. Further, as compared with Comparative Examples 7 to 11, the ratio of etching rate of Cu to Mo is adjusted by simultaneously using glycolic acid, aspartic acid and glutamic acid and using either EDTA or lower alcohol 1-propanol. Thus, it was possible to realize an etching solution having a preferable cross-sectional shape of the etching portion and a long bath life without precipitates.

The etching solution of the present invention is not limited to products such as liquid crystal displays, plasma displays, FPDs such as organic EL, etc. Substrates such as glass substrates, silicon substrates, amorphous silicon substrates, metal oxide substrates or underlayers made of these materials In the aspect using the wiring in which the molybdenum layer and copper layer which were formed on top were laminated | stacked, it can utilize widely.

1 substrate 2 copper layer 3 molybdenum layer 4 resist (layer)
5 taper angle 6 slope 10 undercut part

Claims

With hydrogen peroxide,
Inorganic acid,
With an acidic organic acid,
Neutral organic acid,
An amine compound,
An etching solution for a multilayer film comprising a copper layer and a molybdenum layer characterized by containing a hydrogen peroxide decomposition inhibitor.
An etchant for a multilayer film comprising a copper layer and a molybdenum layer according to claim 1, which does not contain an azole compound, a phosphorus compound and a fluorine compound.
An etching solution for a multilayer film comprising a copper layer and a molybdenum layer according to any one of claims 1 and 2, further comprising an aminocarboxylic acid-based chelating agent.
The etching solution according to any one of claims 1 to 3, wherein the inorganic acid is at least one of sulfuric acid and nitric acid.
The etching for a multilayer film including a copper layer and a molybdenum layer according to any one of claims 1 to 4, wherein the acidic organic acid contains three kinds of glycolic acid, aspartic acid and glutamic acid. liquid.
The etching solution for a multilayer film according to any one of claims 1 to 5, wherein the neutral organic acid is any one of glycine and β-alanine. .
The etching solution for a multilayer film containing a copper layer and a molybdenum layer according to any one of claims 1 to 6, wherein the amine compound is 1-amino-2-propanol.
The etchant for a multilayer film according to any one of claims 1 to 7, wherein the hydrogen peroxide decomposition inhibitor is phenylurea or a lower alcohol.
9. The aluminocarboxylic acid-based chelating agent is any one of ethylenediaminetetraacetic acid, hydroxyethyliminodiacetic acid, and ethylenediamine-N, N'-disuccinic acid. An etching solution for a multilayer film comprising a copper layer and a molybdenum layer described in 4.
Furthermore, polyethylene oxide is included, The etching liquid for multilayer films containing the copper layer and the molybdenum layer as described in any one of the Claims 1 thru | or 9 characterized by the above-mentioned.
The etchant for a multilayer film containing a copper layer and a molybdenum layer according to any one of claims 1 to 10, further comprising 500 to 7,000 ppm of copper ions.
Inorganic acid,
With an acidic organic acid,
Neutral organic acid,
An amine compound,
Hydrogen peroxide decomposition inhibitor,
An etching concentrate for a multilayer film comprising a copper layer and a molybdenum layer, characterized in that it contains water.
Inorganic acid,
With an acidic organic acid,
Neutral organic acid,
An amine compound,
Preparing an etching solution containing a hydrogen peroxide decomposition inhibitor and water, water, and hydrogen peroxide;
A method of etching a multilayer film including a copper layer and a molybdenum layer, comprising the step of bringing the etching solution for multilayer film into contact with a substrate to be treated.
In the step of bringing the etching solution for multilayer film into contact with the substrate to be treated,
The multilayer film according to claim 13, wherein the pH of the etching solution for a multilayer film is in the range of 2 to 5, and the solution temperature is 18 to 35C. How to etch film.